Electric-arc lamp



Sept. 4, 1928.

I. J. LAVOKSIER ELECTRIC ARC LAMP Filed Oct. 1924 A W 7mm 1w; 0?

Patented Sept. 4, 1928.

UNITED STATES PATENT OFFICE.

IAN JEAN LAVOISIER, OF NEW ORLEANS, LOUISIANA, ASSIGNOR, BY MESNEASSIGN- MEN'I'S, TO THE BURDIGK CORPORATION, OF MILTON, WISCONSIN, A.CORPORATION OF DELAWARE,

ELECTRIC-ABC LAMP.

My invention relates to electric arc lamps.

It will be explained as applled to a lam particularly adapted fortherapeutlc uses a though not limited to this field.

One of the objects of my invention is to provide an improved electricarc lamp.

Another object is to provide an improved electrode for are lamps.

Another object is to provide a method of .10 making highly conductiveelectrodes composed of materials which are normally highlynon-conductive under ordinary temperatures and voltages.

Another object is to provide a highly re- 1 fractory electric arcelectrode.

Another object is to provide an are discharge -whose spectralcharacteristics may be made to closely approximate those of sunlight athigh altitudes.

Another object is to provide electrodes for are discharges of variousspectral characteristics.

A further object is to provide improved means for effecting theformation of the are discharge between the electrodes.

Other objects and advantages will hereinafter appear.

The accompanying drawing illustrates somewhat diagrammatically one formwhich my improved lamp may assume.

I have found that intense and hi hly satisfactory arc discharges may bepro need be tween electrodes which contain zirconium and yttrium oxides.At ordinary room temperatures of around 20 to 38 degrees centigradezirconium and yttrium oxides are highly nonconductive but I have foundthat these oxides may be combined with other materials and so treated asto provide a substance which may 40 be readily formed into electrodesand have suificient conductivity to produce satisfactory arcs whensubjected to normal service voltages at ordinary room temperatures. Thearc is readily formed and easily maintained 4!! and its spectralcharacteristics will very closely approximate those of sunlight at hi halti tudes. Furthermore, I have found t at by adding other substancesthe spectral characteristics of the arc discharge may be quitematerially varied to meet special requirements of therapeutic and otherfields of use.

The method which I have found suitable for providing my improvedelectrodes is as follows:

Zirconium oxide and yttrium oxide in finely powdered condition are mixedtogether with a suitable binder, such as hydrogel (zirconium hydroxide),to form a paste. I have found that the zirconium and yttrium oxides whenpowdered suificiently fine to pass through a screen of 120 mesh willgive good results. The proportions of the two oxides which I have foundsatisfactory are approximately 7 5 to 85 per cent chemically pure zirconium oxide and 25 to 15 per cent chemically pure yttrium oxide. Enoughof the binder, such as hydrogel, is added so that the mixture of thethree ingredients forms a paste which may be worked or molded intosuitable sizes and shapes for the subsequent treatments.

The pasty mixture may then be worked, or compressed in suitable molds,to form electrodes of the desired shape. I have found that fortherapeutic use substantially cylindrical electrodes of about diametergive good results. The paste should be sufliciently plastic to permitits being formed into the proper size and shape and yet stiif enough toretain that form during the remainder of the treatment.

The formed electrodes are next dried at ordinar room temperature, suchfor example, as etween 20 to 38 degrees Centigrade for a suflicientlength of time to thoroughly dry the mass. The length of time'requiredwill depend upon the consistenc of the paste and the atmospherehumidity, ut from two to four days will ordinarily sufiice.

After being dried as above described the electrodes are placed in asuitable furnace and the temperature gradually raised, preferably a fewdegrees an hour, until the mass is dehydrated. Then the temperature israised more rapidly if desired, until the surface of the electrode issintered. Ordinarily this sintering temperature will be between 1900 and2200 degrees centigrade. The proper temperature will be evidenced by theglazing or vitrifying of the electrodes. After the electrodes arethoroughly glazed or vitrified they are ready for use.

If it is impracticable to obtain chemically stant, and possesses ve pureyttrium oxide free from the erbium or terbium groups of metals, thefinished electrodes may not be sufliciently conductive at ordinary roomtem ratures and service voltages to give g results. However, the pro rconductivity may be obtained by inclusi ng in the p mixture a suflicientquantity of any the following substances :--zirconium carbide, titaniumearbide, tungsten carbide, or tantalum carbide, or ferro-alloys of anyof these elements. The amount of any of these substances which may berequired 'will depend u n the degree of purity of the yttrium oxi e andthe conductivity desired in the finished electrode. Ordinarily theamount will be small.

The electrodes produced by the foregoing method are conductive atordinary room temperatures, such for example, as 20 to 38 degreescentigrade and at ordinary service voltages, such, for example, as 110to 220 volts. The are produced when the electrodes are subjected to suchvoltages is intense, conclosely the spectral characteristics of sunligt.

In order to increase the intensity of the visible rays produced by theare, calcium fluorid or preferably titanium carbide, may be added to themixture of zirconium and atrium oxides. I prefer titanium carbide causeit is a better conductor of electricity than the other substances.

The percentage of actinic or ultraviolet ray emission from the arc maybe increased by adding tungsten, tantalum or molybdenum or their saltsto the mixture of zirconium and yttrium oxides.

The percenta of infra-red ray emission may be increase by the additionof thorium, cerium or silicon.

The accompanying drawing shows one form of lamp particularly suited fortherautic uses. It has an exhausted or inert as sided bulb 1 forming aclosed chamber %or the electrodes. The bulb may be made of glass, quartzor other suitable transparent or translucent material. If an intenseemission of ultra-violent rays is desired, the bulb may be made entirelyof quartz, although I prefer to provide merely a quartz window 2 at thebottom which may be sealed to a glass side wall b suitable means such asnascent silver chlori e under heat. The upper end of the bulb 1 issealed in the usual manner and secured to a suitable metallic supportand connector 3 of any appropriate type. I have shown a supportingconnector having projecting pins 4 for cooperation with bayonet slots inthe metal shell 5 of a suitable plug recvigitacle.

ithin bulb 1 there is an insulating support 4 which carries-twoconducting electrode supports 6 and 7. Electrode supports 6 and 7 may beformed from stri s of suitable metal such as bronze or steel. upport 7in particular is made flexible so that, although it is normally biasedaway from support 6, it may be moved toward the same to bring theelectrodes together, as will be hereinafter described. Electrode pencils8 and 9, formed as hereinbefore described, are secured to supports 6 and7, respectively, by suitable means such as screw clamps.

Support 7 is provided with an armature 10 which is in a position to beattracted by a small electromagnet 11 rigidly secured to insulatingsupport 4.

Support 6 is connected to the metal connector 3 by a conductor 12 sealedthrough the walls of bulb 1 and to one terminal of electromagnet 11 by aconductor 13. Support 7 is connected to a lamp contact 14 which isinsulated from connector 3 and ada ted to engage a contact 15 ofreceptacle 5. be other terminal of magnet 11 is connected to a lampcontact 16 which is insulated from contact 14 and connector 3 and isadapted to engage a receptacle contact 17.

One of the service wires 18 is electrically connected to the receptacleshell 3. The other service wire 19 is connected to receptacle contact 16and, through a suitable switch 20, to a receptacle contact 17 The lampis operated by closing switch 20 which completes a circuit throughelectromagnet 11. The energization of electromagnet 11 attracts armature10, bringin electrodes 8 and 9 into on gement and tlierebv completing acircuit t erethrough. Switch 20 is thereupon opened de-energizingelectromagnet 11 and rmitting electrodes 8 and 9 to separate anfidrawing the are therebetween.

I claim 1. An electric arc electrode comprising a dehydrated and lazedmixture of zirconium and yttrium oxi e.

2. An electric arc electrode comprising a dehydrated and glazed mixturecontaining zirconium and yttrium oxides in approximately the followingproportions: zirconium oxide, to yttrium oxide, 25% to 15%.

In testimony whereof I hereunto subscribe my name.

